startup animations info (rules/settings, not actual designs)
 

I'm interested in customizing the startup/shutdown animations (I'm looking for info on how it works and how to change it, not asking for new designs of fun images etc.). I've been playing with the settings of Advanced Configurations tool and so far

my HTC startup GIF animation works
Microsoft startup GIF animation works

Carrier Splashscreen doesn't
Microsoft shutdown doesn't
none of the WAVs play

when it starts up, it buzzes, then I see a black screen with "htc" in the middle of it, and then red text at the bottom appears (firmware versions and such, I think).

Is there a tutorial somewhere listing the order in which these things are supposed to run, the various rules for file formats/sizes, etc. so that I can figure out why some of it is being played and some not?

Mike